It is desired to make nanometer size particles (5 to 30 nanometers in diameter or largest dimension) of nickel and nickel oxide for applications in catalysis, electronics, and magnetics. Several physical and chemical methods such as metal vapor synthesis, thermal decomposition of a nickel aerosol precursor, and sol-gel methods, can be used to synthesize nanocrystalline NiO. The NiO materials prepared by these methods are generally spherical particles with a size of less than ten nanometers when exposed to a temperature less than 400° C. However, the size of these particles increases to greater than about twenty nanometers when they are heated over 700° C. Moreover, there is little control of the morphology of the spherical particles with such methods.
There is a need for a method of producing nanometer size particles of nickel oxide having high temperature stability. There is also a need for producing new crystalline forms (i.e., other than spherical forms) of thermally stable nanometer size particles of nickel oxide.